Manual steel files N° 10 and 15. Used until they move freely in the canal.

Objectives:

• Secure and prepare the access for CMA into the coronal 2/3 of the canal.

Step 2

Flaring the coronal and middle part of the canal:

Instruments used:

CORONAL and MEDIAN. CORONAL C

flares out the coronal part of the canal.

MEDIAN M

enlarges the middle part of the canal.

Objectives:

• Straighten the access and enlarge the root canal entries to provide continuity between the pulp chamber and the canals, so as to allow the tools a free access to the apical one-third.

Step 3

Determining the working length:

Instruments used:

Manual steel files N° 10 and 15. Used until they move freely in the canal.

Objectives:

• Determining the working length. • Preparing for the nickel-titanium rotary instruments to pass safely all the way to the apical one-third.

Step 4

Enlarging the apical portion of the canal:

Instruments used:

APICAL FINE A1 is used on the whole length of the root canal, to be followed by APICAL A2.

Objectives:

• Preparing the apical portion. • Making a space where the irrigation solutions can collect. • Providing the apical taper which will give the best obturation. • Keeping apical diameter small.

Recommendations

• Nickel-titanium rotary instruments must be used in a portion of the canal which has been explored and prepared previously with a manual file number 15.

• Examine the instruments before and after each use. Discard the tool if there is the slightest deformation. • Speed: 300 to 400 rpm. • Torque: 2 to 3 N for all instruments. • Movement: progression towards the apex by continuous short (1mm to 3 mm) and rapid up-and-down

strokes, finishing off with a « brushing » movement on the root canal walls. • Time: 5 or 10 seconds per rotary instrument. • The nickel-titanium rotary instruments must never be forced. • Properly clean the instrument after each removal. • The canal must be copiously irrigated with sodium hypochlorite each time the instrument

has been introduced. • Use of chelating gel is advised in order to facilitate work with the tools. • If progression with A1 is hindered, go again with K 15 file and M. If is hindered with A2, go again

Aim To determine the efficacy of Sonicare CanalBrush irrigation for root canal cleaning.

Methodology Fifty human molar root canals were shaped with sequential NiTi rotary instruments up to size F3 (size 30, 0.09 taper; ProTaper system) and then enlarged apically with a Profile size 40, 0.04 taper. Five different irrigation protocols were tested (n = 10 canals per group) with 2 mL of distilled water (control, group I) or 2.5% NaOCl (control group II and test groups III, IV and V) between instrument size changes. Group III–IV received a final rinse with 17% EDTA for one min. This was extended by 30 s in group IV, whereas group V received this additional 30 s of 17% EDTA sonically dispersed with a Sonicare CanalBrush. For cleanliness evaluations, roots were split longitudinally, examined with scanning electron microscopy and scored according to Hülsmann et al. (1997) for debris and smear layer on the surface of the root canal wall. Walls were assessed at the coronal, middle and apical thirds. Data were analysed with the Kruskal–Wallis and Mann–Whitney tests.

Results Irrigation with 17% EDTA significantly reduced debris and smear layer scores (P < 0.05) compared to controls. The coronal and middle thirds had lower debris and smear layer scores than the apical third (P < 0.05). In all thirds, sonic agitation of the irrigant with a CanalBrush (group V) resulted in significantly cleaner canal walls compared to all other groups (P < 0.05).

Conclusions Irrigation by agitation with the Sonicare CanalBrush improved root canal debridement in the coronal, middle and particularly the apical thirds of the root canal.